The present invention relates to a hydroxyl group-containing betaine compound, a long-chain alkyl group-containing betaine compound, and processes for producing said compounds.
The betaine compound has both a cationic group and an anionic group within its molecule and, because of this structural feature, has been attracting attention as an. amphoteric surfactant in recent years. Amphoteric surfactants have many beneficial properties such as exceptionally high resistance to hard water and low toxicity, and are used with advantage in various applications such as surfactants, bactericides, antistatic agents, softening agents, rust inhibitors and so on.
Japanese Kokai Publication Hei-5-32600 discloses a process for producing a betaine compound which comprises reacting an aliphatic primary amine with a quaternary ammonium compound having a defined structure at 6xe2x89xa6pH less than 8 and further reacting the reaction product with a defined halogenated lower carboxylic acid at 6xe2x89xa6pH less than 8. The betaine compound produced by this process has foaming and detergent properties so that it can be used as a surfactant for hair and body cleansing. However, in order that a variety of properties other than foaming and detergent properties may be imparted to such a betaine compound to thereby expand its scope of application, a further investigation into related compounds was needed.
Japanese Kokai Publication Hei-5-294905 discloses a carbobetaine compound and a process for its production. This process for producing a carbobetaine compound comprises reacting a defined amino compound with a defined halogen-containing salt. The carbobetaine compound obtainable by this process has an emolient action on the hairs and skin so that it finds application as an emolient in hair care and skin care products. However, with regard to such carbobetaine compound, too, further investigations are needed into related compounds in order to impart a variety of properties other than emolient activity for an expanded scope of application.
The present invention, developed in light of the above state of the art, has for its object to provide a hydroxyl group-containing betaine compound and a long-chain alkyl group-containing betaine compound, both of which are highly biodegradable and useful as surfactants, bactericides, antistatic agents, softening agents, rust inhibitors, resin-modifying agents, and synthetic intermediates, as well as processes for producing said compounds.
The present invention relates to a hydroxyl group-containing betaine compound of the following general formula (1): 
wherein R1 and R2 may be the same or different and each represents a hydrogen atom, a C1-8 hydrocarbon group or a C1-8 hydrocarbon group having a hydroxyl group, exclusive of the case in which both of R1 and R2 respectively represent a hydrogen atom; in case neither R1 nor R2 represents a hydrogen atom, R1 and R2 may be joined to each other through a single bond or through at least one kind of element selected from the group consisting of O, S and N; R3 represents a hydrogen atom, a methyl group or a hydroxymethyl group; A represents a C2-25 hydrocarbon group.
In a further aspect, the present invention relates to a process for producing a hydroxyl group-containing betaine compound of the following general formula (1): 
wherein R1, R2, R3 and A are respectively as defined above,
which comprises a step of reacting a xcex2-alanine derivative of the following general formula (2): 
wherein R1, R2 and R3 are respectively as defined above, with a monooxirane compound.
In a further aspect, the present invention relates to a long-chain alkyl group-containing betaine compound of the following general formula (3): 
wherein R6 and R7 maybe the same or different and each represents a hydrogen atom or a C1-8 hydrocarbon group, exclusive of the case in which both of R6 and R7 respectively represent a hydrogen atom; in case neither R6 nor R7 represents a hydrogen atom, R6 and R7 may be joined to each other through a single bond or through at least one kind of element selected from the group consisting of O, S and N; R3 and A are as defined above; R4 and R5 are such that whichever one of them represents a hydrogen atom and the other represents a C5-30 hydrocarbon group; X represents a hydrogen atom or xe2x80x94COOM, where M represents a hydrogen atom, a metal atom or an ammonium group.
In a still further aspect, the present invention relates to a process for producing a long-chain alkyl group-containing betaine compound of the following general formula (3): 
wherein R6, R7, R3, A, R4, R5 and X are respectively as defined above,
which comprises a step of reacting a hydroxyl group-containing betaine compound of the following general formula (6): 
wherein R6, R7, R3 and A are respectively as defined above, with either a long-chain alkyl group-containing carboxylic acid of the following general formula (4): 
wherein R4, R5 and X are respectively as defined above, or a long-chain alkyl group-containing carboxylic anhydride of the following general formula (5): 
wherein R1 and R5 are respectively as defined above.